Twentieth Century World History for Beginners

Twentieth century world history for beginners is one long chain of cause and effect. Nations were built, those nations built empires, the empires collided in two world wars, the winners split into two camps, and then the empires ended. If you hold that chain in your head, the dates and names have somewhere to go.

This guide walks the chain in order, in plain words. It does not try to tell you everything. It tells you what led to what, and it points to a longer article on each big turn. Read it once from top to bottom, then come back to the parts you want to know more about.

Start with the problem: why one century is hard to learn

Most people meet the twentieth century as a pile of separate topics. One lesson is about trenches. Another is about Hitler. Another is about a wall in Berlin. Each topic makes sense alone, but nothing connects them, so nothing stays in memory.

The fix is to ask one question at every step: what problem did the last step leave behind? A peace treaty that humiliates the loser leaves a loser who wants revenge. A war that exhausts two empires leaves colonies that no longer believe in them. Once you ask this question, the century stops being a list and becomes a story.

Use three simple ideas as handles:

Nation: a group of people who feel they belong together and want one government.
Empire: one state that rules other peoples, often far away, without their consent.
Alliance: a promise between states to help each other if one is attacked.

Almost every event below is one of these three ideas in trouble.

Making nations: Garibaldi, Bismarck, Meiji and Lincoln

Before the First World War, the biggest change was not a war between great powers. It was the making of big states. In the middle of the nineteenth century, Italy was a patchwork of small kingdoms and papal lands. Giuseppe Garibaldi, a soldier who led volunteers in red shirts, helped to join them into one Italian state. In the same years, Otto von Bismarck used three short wars, planned with great care, to pull the German states into one empire under the king of Prussia.

On the other side of the world, the same pattern appeared. In the United States, Abraham Lincoln fought a civil war to keep the union together, and the country that came out of it was more of a single nation than before. In Japan, a group of young samurai and officials ended the old shogun system in 1868 and built a strong state in a generation. You can read how that worked in Meiji Restoration: how Japan changed in a generation.

What these cases share is a recipe. A state gets a central government, a national army, railways, schools that teach one language, and a feeling of shared story. That recipe makes a country strong. It also makes a country proud, and a proud, strong country with a big army starts asking what it deserves.

Remember this for later. The recipe worked so well that every ambitious government copied it, and by the start of the twentieth century there were several strong nation states packed close together, especially in Europe.

The scramble for empire and the people who resisted it

Strong nations wanted resources, markets and prestige. Many of them found these overseas. In the decades before the First World War, European states took control of almost all of Africa and large parts of Asia. Britain and France held the largest empires. Germany, Italy and Belgium joined late and held less. Japan also began to build an empire in East Asia, and the United States took islands in the Pacific and Caribbean.

Empire meant more than flags on a map. It meant that railways, mines and plantations were built to send goods out, not to help local people. It meant that borders were drawn in distant capitals with little care for who lived where. Those borders caused trouble for a long time after the empires left.

People resisted from the start. Some fought armies and lost. Some built movements that used schools, newspapers and petitions. Some, later, used the empires' own words against them: if the ruling states said they stood for freedom and self rule, why not for us? Keep this question in mind. It comes back in the last part of this guide.

Empire also explains why a quarrel in one part of Europe could drag in the whole world. The great powers had colonies and trade routes everywhere, so a war between them could not stay local.

Sarajevo to Versailles

By the summer of the assassination, Europe was divided into two alliance blocs. On one side stood Germany and Austria-Hungary. On the other stood France, Russia and Britain. Each bloc had made promises to help its members. Each had made war plans that depended on moving armies by rail on a strict timetable.

On 28 June, in the summer the war began, a young Bosnian Serb named Gavrilo Princip shot the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand, in the city of Sarajevo. The assassination was a spark. The dry wood was the alliances, the timetables and the pride. Austria-Hungary blamed Serbia, Russia stood behind Serbia, Germany stood behind Austria-Hungary, and within weeks the great powers were at war. The full chain, step by step, is in how the Sarajevo assassination started a world war.

Most people on all sides expected a short war. It was not short. On the Western Front, in France and Belgium, the armies dug lines of trenches and faced each other for years. Machine guns and artillery made open attacks deadly. Soldiers lived in mud and cold, with rats, lice and long waits broken by sudden terror. Generals kept ordering attacks, and each one cost thousands of lives for a few hundred metres of ground.

The war was not only in the trenches. It was fought at sea, in the Middle East, in Africa and on the Eastern Front, where Russia faced Germany and Austria-Hungary. In the third year of the war, Russia, worn out by losses and hunger, saw its government collapse and then a revolution led by the Bolsheviks. The Bolshevik government made peace the following winter and left the war. That same year, the United States joined the other side, bringing fresh soldiers and supplies. By the autumn of the fourth year, Germany could not go on, and an armistice stopped the fighting.

Then came the peace. At Versailles, near Paris, the winners wrote a treaty for Germany. It took away land, limited the army, and made Germany accept blame and pay large sums. The winners had different aims. France wanted safety from Germany. Britain wanted balance. The United States wanted a lasting order, but did not stay to enforce it. The result pleased almost nobody. Germans felt humiliated, and the winners were not united enough to hold the line. The peace that was meant to end war left a grievance.

This is the first lesson of the century: a harsh and badly enforced peace can plant the next war.

Hitler to Hiroshima

The twenty years between the wars were unstable. The world economy was weak. A crash on the New York stock market began in the United States and spread. Factories closed, banks failed and millions lost work. In many countries, people lost faith in the old political order and listened to leaders who promised strength and a simple answer.

In Germany, Adolf Hitler and the Nazi party rose by blaming the Versailles treaty, the economy and minorities, above all Jewish people, for the nation's pain. Hitler became chancellor in the early 1930s and turned Germany into a dictatorship. He built up the army against the treaty, took back land and then took over other states. Britain and France tried to avoid war by giving ground. When Germany invaded Poland, they stopped giving ground, and the Second World War began.

It was larger than the first. Germany swept across much of Europe. The Soviet Union, first tied to Germany by a pact, was invaded two years into the war. Japan, which had already invaded China, attacked the United States and the European colonies in Asia later that year. The war then ran on two great stages, Europe and the Pacific.

Several turning points are worth knowing. The Battle of Stalingrad, in the Soviet Union, ended with a German army surrounded and destroyed; read why Stalingrad was the turning point for the reasons. The landings in Normandy opened a second front in the west. In Asia, the United States and its allies pushed back Japanese forces island by island.

The war also brought crimes on a scale that shocked the world. The Nazi state murdered about six million Jewish people and millions of others in the Holocaust. This was not a side effect of the war. It was a goal of the regime, carried out with the help of ordinary officials, police and railway workers across occupied Europe. Any honest history of the century must say this plainly.

The war in Europe ended in May, and that summer the United States dropped atomic bombs on Hiroshima and Nagasaki, and Japan surrendered. Historians still argue about whether the bombs were needed to end the war. It is fair to say that they ended the war quickly and began a deep fear: that a future war could destroy whole cities, or more.

The Cold War without a direct war

After the Second World War, two states were far stronger than any other: the United States and the Soviet Union. They had fought on the same side, but they had very different systems. One was a capitalist democracy. The other was a one party state with a planned economy. Each feared the other and each wanted friendly governments in as many countries as possible.

The result is called the Cold War, because the two powers never fought each other directly. Both held nuclear weapons, and both knew that a direct war could destroy them. So they competed in other ways. They built alliances, backed rival sides in wars in Korea and Vietnam and in many smaller conflicts, raced to put satellites and then people into space, and spent huge sums on weapons.

Germany sat at the centre. After the war it was split into zones, and then into two states, with the city of Berlin divided inside the eastern one. Many East Germans left through Berlin to the west. Within sixteen years of the war's end, the eastern government built a wall to stop them. The reasons, and what the wall did to families, are in why the Berlin Wall was built.

There were moments when the world came close to the edge, such as the Cuban missile crisis, when both sides stepped back from the brink. The Cold War did not end with a battle. The Soviet economy could not keep up, the people of eastern Europe pushed for change, the Berlin Wall opened in the last months of the 1980s, and the Soviet Union itself broke apart soon after.

The second lesson of the century: a conflict can shape the whole world even when the two main players never shoot at each other.

The end of empires

While the Cold War ran, another change ran alongside it. The old empires ended. The Second World War had left Britain, France and the Netherlands weak and in debt. They could no longer afford to rule far away by force. At the same time, the peoples they ruled were better organised and more sure of what they wanted.

India is the best known case. Mohandas Gandhi and the Indian National Congress built a mass movement that used non violent protest. The Salt March turned a tax on salt into a symbol everyone understood; see why Gandhi's Salt March worked. India and Pakistan became independent in the years just after the war, and the division brought terrible violence and the movement of millions of people.

After India, the pace grew. Many Asian states became independent in the following years. In Africa, a great number of countries gained independence from the late 1950s onward, some peacefully and some after long wars. In some places, such as Algeria and Vietnam, independence came after bitter fighting. In others, it came by negotiation.

Independence did not solve everything. The borders drawn by empires often cut across peoples and joined rivals. Economies had been built to export raw materials. The young states then had to build schools, courts and industries, often while the Cold War powers pushed them to pick a side.

The third lesson: an empire is easier to build than to keep, and it ends when its ruler can no longer afford it and its subjects no longer accept it.

A worked example: following one chain

Try the method on a single question: why did Germany become a dictatorship?

At the end of the First World War Germany lost the First World War. Many Germans did not feel they had been beaten on the battlefield, which made the defeat hard to accept.
The Versailles treaty took land, limited the army and demanded payments. Many Germans felt it was an insult.
The weak young democracy faced hard years, and then the crash on Wall Street threw millions out of work.
People who had lost jobs and savings listened to a party that offered someone to blame and a promise of strength.
Politicians who thought they could control Hitler gave him the post of chancellor, and he used it to end democracy.

Each step answers the question left by the one before. This is how to read any event in the century. It does not excuse anyone. It explains how people ended up where they did, which is the whole point of studying history.

Common mistakes when learning this century

Learning dates without links. A list of dates is hard to remember. A chain of causes is easy.
Treating the wars as one story. The second war grew out of the first, but it had its own causes, and the Holocaust and the war in Asia need their own attention.
Forgetting the world outside Europe. The century was also made in Delhi, Beijing, Algiers, Tokyo and Lagos.
Looking for one villain or one cause. Most big events had several causes working together.
Mixing up the Cold War with a hot war. It was a competition, with real wars on its edges.

Quick reference

Turn	What happened	What it left behind
Making nations	Italy, Germany, Japan and the United States became strong single states	Proud, armed states close together
Scramble for empire	Europe took most of Africa and much of Asia	Borders and resentments
First World War	Sarajevo, trenches, Russian revolution, armistice	A harsh peace and a weak order
Second World War	Hitler's Germany, Japan, the Holocaust, atomic bombs	Two superpowers
Cold War	United States against the Soviet Union, no direct war	A divided Germany and a nuclear fear
End of empires	India, then Asia and Africa	Many young states with inherited borders

Questions people ask

Where should a beginner start with twentieth century history?

Start with the First World War, and specifically with how it began. The causes are a good lesson in alliances and pride, and nearly everything later in the century traces back to its results. After that, follow the chain forward in order.

Was the Second World War caused by the Treaty of Versailles?

The treaty was one cause, not the only one. The world economic crash, weak democracies, Hitler's aims and the choices of other governments also mattered. Historians weigh these in different ways, and it is fair to say that Versailles made the rise of an angry movement easier.

Why was it called the Cold War?

Because the United States and the Soviet Union never fought each other in open war. They competed with money, weapons, spies, alliances and wars fought in other countries. Both held nuclear weapons, which made a direct fight too dangerous.

How did the empires end so quickly?

They did not all end at once, but they ended within a few decades. The wars left the ruling states tired and poor, independence movements had grown strong, and the ideas of self rule that the empires themselves spoke about were turned against them.

Do I need to remember every date?

No. Learn the order of the big turns and a handful of anchor dates, then let the rest attach to them. Understanding why something happened is worth more than a long list of years.

Learn this in five minutes

The track "Sarajevo to Versailles" gives you the first half of this chain in five short lessons: the assassination, life in the trenches, the Christmas truce of the first winter, Russia leaving the war and the peace that set up the next war. Each lesson is one story and one takeaway, so you can build the century a step at a time.